The present invention is directed to weight distribution trailer hitches, and more particularly to a weight distribution trailer hitch with a novel safety clip that prevents dislodgement of the safety pin.
Weight distribution trailer hitches are well known in the art. The purpose of a weight distribution hitch is to prevent the weight of the trailer from causing the juncture of the tow vehicle and the trailer to drop, which can lead to the front of the tow vehicle raising up. This is an unsafe condition that can place undue stress on various elements of the trailer and the tow vehicle. The weight distribution hitch removes excess weight from the tow vehicle's rear axle and distributes the excess weight to the front wheels of the tow vehicle and the trailer wheels.
Reference to weight distribution trailer hitches can be found, for example, in U.S. Pat. No. 6,722,682 to Valliere et al., U.S. Pat. No. 5,868,414 to McCoy et al., and U.S. Pat. No. 5,984,341 to Kass et al., the contents of each of which are fully incorporated herein by reference.
Weight distribution hitches normally utilize a shank formed of a tubular shaft that is secured to the tow vehicle with a hitch pin. A shank bar is a rectangular member with spaced holes that mounts vertically to the shank and is used to set the height of the hitch. The hitch includes a U-shaped section that receives the shank bar, and includes bolt holes that align with holes on the shank bar so that the hitch may be bolted to the shank with an adjustable height to accommodate different size trailers and tow vehicles. The hitch includes a pair of weight distribution rods that have upturned proximal ends. The distal ends of the weight distribution rods are configured to secure a lift chain that connects the weight distribution rods to the trailer. The upturned proximal ends of the distribution rods are releasably received from below in two tubular cavities in the hitch. To prevent the distribution rods from falling out of the hitch's tubular cavities, a pin is used that passes through the wall of the tubular cavity and into an aperture in the distribution rods. The lift chains serve to establish a maximum distance that the weight distribution rods extend below the trailer, which in turn prevents the hitch from dropping much below its unhitched elevation. This system causes much more balanced towing and helps to prevent tipping or loss of control of the trailer.
It has been discovered that the pin used to maintain the weight distribution rods in the tubular cavities of the hitch can become inadvertently dislodged when subject to the routine vibrations of towing conditions, particularly on uneven roads and at higher speeds. Loss of the pin can result in separation of the trailer from the towing vehicle, loss of control of the trailer, or damage to the hitch. Therefore, it is also known in the art to provide a spring clip between the head of the pin and the outer surface of the tubular cavity on the hitch. The spring clip is riveted or otherwise mounted at a lower surface to the outer surface of the hitch's tubular cavity, and the spring clip includes a vertical slot that receives the shank of the pin. The spring clip's upper portion is biased to bear against (or generally against) the outer surface of the cylindrical cavity, while the bottom portion is mounted directly to the same surface. When it is desired to remove the weight distribution rods, the clip can be pulled back manually against its bias away from the surface of the hitch's tubular cylinder, allowing the pin to be removed from the proximal upturned end of the weight distribution rods. With the pin removed, the rods can be easily removed from the hitch and the hitch can then be disassembled, adjusted, or removed from the tow vehicle/trailer. When it is desired to reassemble the system, the clip is pulled away from the surface of the hitch so that the pin is extracted from the cavity. With the pin displaced, the weight distribution rods can be inserted into the cavity and the spring clip released to position the pin back in its designated position to once again retain the weight distribution rods in the hitch.
The present inventor has discovered that the above described system still has a shortcoming, namely the propensity for the pin to become separated or lost. The pin may become lost due to the clip's loss of resiliency after many repeated openings, to the point where the clip no longer bears against the surface of the hitch and gradually becomes more and more separated from this surface, until eventually the vibration of the towing operation can cause the pin to become dislodged. The pin can also become dislodged while the weight distribution rods are being inserted or removed from the hitch. That is, if the user does not open the spring clip far enough, the pin will not clear the cavity and the rods cannot be removed/inserted. However, if the clip is opened too far, the pin may become dislodged and fall into the dirt, roll away, or become lost. With repeated use, the spring clip can begin to lose its capacity to snap back into position and lose its spring action, leading to overextension of the clip. When trying to insert or remove the weight distribution rods, the loss of the pin can be particularly disconcerting and can present a dangerous situation. The present invention addresses these shortcoming and provides an economic solution to prevent dislodgement of the pin from the hitch.